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Single Package RooftopGas Heat/Electric CoolingVertical Air Flow Unit15, 17.5, 20, 25, 27.5 Tons
48TC 17, 20, 24, 28, 30 with Puron® (R-410A) Refrigerant
Unit shown with economizer and power exhaust.
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Carrier’s WeatherMaker® 15 to 27.5 tonrooftop unit (RTU) was designed by cus-tomers for customers. With “no-strip”screw collars, handled access panels, andmore, we’ve made your unit reliable andeasy to install, maintain, and use.Easy to install:These WeatherMaker® units aredesigned for dedicated factory-suppliedvertical air flow duct configurations.Designed to fit on pre-installed curbs byanother manufacturer, these units alsofit on past designed Carrier installedcurbs with a new certified and autho-rized adapter curb. This cabinet designalso integrates a large control box thatgives you room to work and room tomount Carrier accessory controls.Easy to maintain:Easy access handles by Carrier providequick and easy access to all normallyserviced components. Our “no-strip”screw system has superior holdingpower and guides screws into positionwhile preventing the screw from strip-ping the unit’s metal. Take accuratepressure readings by reading systempressures with panels in place as com-pressors are strategically located toeliminate any air bypass.Easy to use:The central terminal board by Carrierputs all your connections and trouble-shooting points in one convenientplace, standard. Most low voltage con-nections are made to the same boardand make it easy to find what you’relooking for and easy to access it.Reliable:Each unit comes with precision sizedand tested scroll compressor that isinternally protected from over tem-perature and pressures. In addition,each refrigerant circuit is further pro-tected with a high-pressure and low-pressure switch as well as containing aliquid line filter drier. Each unit is fac-tory tested prior to shipment to helpensure unit operation once properlyinstalled.
Key features:• 2-stage cooling capability with inde-
pendent circuits and control.• Round tube/plate fin (RTPF) avail-
able on all sizes or Novation® all alu-minum condenser (outdoor) coilsavailable on 17-28 sizes only. Specialcoil-coating also available for coastaland industrial environments.
• Energy efficiency ratios (EERs) up to10.8
• IEERs up to 12.0 with single speedindoor fan motor and up to 12.7 with2-speed/VFD indoor fan motor.
• Gas heating efficiencies up to 81%thermal efficiency.
• Dedicated vertical air flow duct con-figuration models.
• Utility connections through the sideor bottom. Bottom connections arealso in an enclosed environment tohelp prevent water entry. Field sup-plied couplings are required.
• Standardized components and lay-out. Standardized components andcontrols make service and stockingparts easier.
• Scroll compressors on all units. Thismakes service, stocking parts,replacement, and troubleshootingeasier.
• Proven Acutrol™ refrigerant meter-ing system.
• Easy-adjust, belt-drive motor avail-able. Motor assembly also contains afan belt break protection system onall models and reliable pillow blockbearing system that allows lubricationthrough the front of the unit.
• Single - point gas / electricalconnection.
• Sloped, composite drain pan shedswater and won’t rust.
• Standardized controls and controlbox layout. Standardized compo-nents and controls make stockingparts and service easier.
• Clean, large, easy to use control box.• Color-coded wiring.• Large, laminated wiring and power
wiring drawings which are affixed tounit make troubleshooting easy.
• Single, central terminal board fortest and wiring connections.
• Fast-access, handled, panels foreasy access on normally accessedservice panels.
• “No-strip” screw system guidesscrews into the panel and capturesthem tightly without stripping thescrew, the panel, or the unit.
• Mechanical cooling 115°F to 30°F(46°C to –1°C) standard on all mod-els. Low ambient controller allowsoperation down to –20°F (–29°C).
• Redundant gas valve for 2-stage gasheating capacity control withinduced-draft flue exhaust design tohelp ensure no flue gas can escapeinto the indoor air stream.
• Exclusive IGC solid state gas con-troller for on board diagnostics withLED error code designation, burnercontrol logic and energy savingindoor fan motor delay.
• Refrigerant filter-drier on each circuit.• High and low pressure switches.
Added reliability with high-pressureswitch and low-pressure switch.
• Many factory-installed options rang-ing from air management econo-mizers, 2-position dampers, manualoutdoor air, plus convenient outlets,disconnect switch and smokedetectors.
• Factory-installed Humidi-MiZer® adaptive dehumidifica-tion system. Available on 17-28 sizes with RTPF con-denser coil models only.
• Standard Parts Warranty: 10-year aluminized heatexchanger, 5-year compressor, 3-year Novation® con-denser coil, 1-year others.
• Tool-less filter removal and installation.
• Staged air volume (SAV™) system utilizes a Variable Fre-quency Drive (VFD) to automatically adjust the indoorfan motor speed between cooling stages. Available on2-stage cooling models 17-30 with electro-mechanicalcontrols or RTU Open Controller. Note that SAV isrequired on all units for installation in the United Statesas per Department of Energy (DOE) efficiency standardof 2018.
Heat OptionsD = Low Gas HeatE = Medium Gas HeatF = High Gas HeatS = Low Heat w/ Stainless Steel ExchangerR = Medium Heat w/ Stainless Steel ExchangerT = High Heat w/ Stainless Steel Exchanger
Sensor OptionsA = NoneB = RA Smoke DetectorC = SA Smoke DetectorD = RA + SA Smoke DetectorE = CO2
F = RA Smoke Detector and CO2
G = SA Smoke Detector and CO2
H = RA + SA Smoke Detector and CO2
J = Condensate Overflow Switch (electromechanical controls only)K = Condensate Overflow Switch and RA Smoke DetectorsL = Condensate Overflow Switch and RA + SA Smoke Detectors
Indoor Fan Options & Air Flow Configuration1 = Standard Static/Vertical Supply, Return Air Flow2 = Medium Static/Vertical Supply, Return Air Flow3 = High Static/Vertical Supply, Return Air FlowB = Med Static High Efficiency Motor/Vertical Supply, Return Air FlowC = High Static High Efficiency Motor/Vertical Supply, Return Air Flow
Refrig. Systems OptionsD = Two stage cooling model with RTPF coilsE = Two stage cooling models with Humidi-MiZer®
Base Unit Controls0 = Base Electro-mechanical Controls (can be used with W7212 EconoMi$er IV)1 = PremierLink™ Controller (for 1-speed motors only)2 = RTU Open Multi-Protocol Controller6 = Electro-mechanical w/ 2-Speed Fan and W7220 Economizer Controller (can be used with W7220 EconoMi$er X)
Service Options0 = None1 = Unpowered Convenience Outlet2 = Powered Convenience Outlet3 = Hinged Panels4 = Hinged Panels and Unpowered Convenience Outlet5 = Hinged Panels and Powered Convenience Outlet
Packaging0 = Standard
Electrical Options A = Non USA models - No (SAV) includedC = Non-Fused DisconnectG = Standard USA models - (SAV) includedJ = 2 Speed Fan Controller (VFD) & Non-Fused Disconnect
Example:Position:
4 8 T C D D 2 4 A 1 A 5 - 0 A 3 G 01 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Model number nomenclature
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AHRI COOLING RATINGS
LEGEND NOTES1. Rated and certified under AHRI Standard 340/360, as appropriate.2. Ratings are based on:
Cooling Standard: 80°F (27°C) db, 67°F (19°C) wb indoor airtemp and 95°F (35°C) db outdoor air temp.IEER Standard: A measure that expresses cooling part load EERefficiency for commercial unitary air conditioning and heat pumpequipment on the basis of weighted operation at various loadcapacities.
3. The 48TC rooftop units meet ASHRAE 90.1-2016, DOE-2018 andIECC1-2015 minimum efficiency requirements when equipped withthe SAV™ (staged air volume) option.
4. 48TC units comply with US Energy Policy Act (2005). To evaluatecode compliance requirements, refer to state and local codes orvisit the following website: http://bcap-energy.org to determine ifcompliance with this standard pertains to your state, territory, ormunicipality.
HEATING RATING TABLE - NATURAL GAS AND PROPANE
NOTES:1. Heat ratings are for natural gas heat exchangers operated at or
below 2000 ft (610 m). For information on Propane or altitudesabove 2000 ft (610 m), see the Application Data section of thisbook. Accessory Propane/High Altitude kits are also available.
2. The input rating for altitudes above 2000 ft (610 m) must be de-rated by 4% for each 1000 ft (305 m) above sea level.
AHRI — Air-Conditioning, Heating and Refrigeration Institute Test Standard
ASHRAE — American Society of Heating, Refrigerating and Air-Conditioning Engineers.
EER — Energy Efficiency RatioIEER — Integrated Energy Efficiency RatioIECC — International Energy Conservation Code*MCHX option is not available on size 30 units.
1. IECC is a registered trademark of International Code Council, Inc.
NOTES:1. Outdoor sound data is measured in accordance with AHRI stan-
dard 370. 2. Measurements are expressed in terms of sound power. Do not
compare these values to sound pressure values because sound
pressure depends on specific environmental factors which nor-mally do not match individual applications. Sound power valuesare independent of the environment and therefore more accurate.
3. A-weighted sound ratings filter out very high and very low frequen-cies, to better approximate the response of “average” human ear.A-weighted measurements for Carrier units are taken in accor-dance with AHRI standard 370.
MINIMUM - MAXIMUM AIRFLOW RATINGS - NATURAL GAS AND PROPANE
RA filter #/ size (in.) 6/ 6/ 6/ 6/ 6/ 6/ 9/ 9/ 9/20 x 25 x 2 20 x 25 x 2 20 x 25 x 2 20 x 25 x 2 20 x 25 x 2 20 x 25 x 2 16 x 25 x 2 16 x 25 x 2 16 x 25 x 2
OA inlet screen #/size (in.)
4/ 4/ 4/ 4/ 4/ 4/ 4/ 4/ 4/16 x 25 x 1 16 x 25 x 1 16 x 25 x 1 16 x 25 x 1 16 x 25 x 1 16 x 25 x 1 16 x 25 x 1 16 x 25 x 1 16 x 25 x 1
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PHYSICAL DATA (COOLING), 15-27.5 TONS, NOVATION® — ALL ALUMINUM COIL DESIGN
Temperature Rise (F) 35-65 35-65 35-65 35-65 35-65
Physical data (cont)
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FACTORY-INSTALLED AND FIELD-INSTALLED ACCESSORIES
NOTES:1. Included with economizer.2. Sensors used to optimize economizer performance.3. See application data for assistance.4. Non-fused disconnect switch cannot be used when unit FLA rating
exceeds 200 amps on 208/230 volt and 100 amps on 460/575 voltunits. Carrier Packaged RTUBuilder selects this automatically.
5. Not for 48TJE024-028 models using 48DP900041, 48DP900051or 48DP900061 roof curbs.
6. FDD (Fault Detection and Diagnostic) capability per CaliforniaTitle 24 Section 120.2i, ASHRAE 90.1-2016 and IECC-2015 FaultDetection and Diagnostic (FDD) requirements.
7. Models with RTU Open DDC controls comply with CaliforniaTitle 24 Section 120.2i, ASHRAE 90.1-2016 and IECC-2015 FaultDetection and Diagnostic (FDD) requirements. PremierLink con-troller is non FDD.
8. Requires a field-supplied 24V transformer for each application.See price pages for details.
9. Not available on units with SAV.
CATEGORY ITEMFACTORY
INSTALLED OPTION
FIELDINSTALLED
ACCESSORY Cabinet Hinged access panels X
Coil Options Cu/Cu outdoor & indoor coils X E-coated outdoor & indoor coils X Pre-coated outdoor coils X
Humidity Control Humidi-MiZer® Adaptive Dehumidification System (17-28 RTPF) X Condenser Protection Condenser coil hail guard (louvered design) X X
Controls
Thermostats, temperature sensors, and subbases XPremierLink™ DDC communicating controller 9 X X RTU Open protocol controller X Smoke detector (supply and/or return air) X X Horn/strobe annunciator 8 X Time Guard II compressor delay control circuit XPhase monitor X
Economizers & Outdoor Air Dampers
EconoMi$er® IV for electro-mechanical controls Non FDD (Low air leak damper models) 6, 9 X X
EconoMi$er2 for DDC controls, complies with FDD (Low Leak and Ultra Low Leak air damper models) 6, 7 X X
EconoMi$er X for electro-mechanical controls, complies with FDD. (Low Leak and Ultra Low Leak air damper models) 6 X X
Motorized 2 position outdoor-air damper 9 X X Manual outdoor-air damper (25%) 9 X X Barometric relief 1 X X Power exhaust–centrifugal blower X X
Economizer Sensors & IAQ Devices
Single dry bulb temperature sensors 2 X X Differential dry bulb temperature sensors 2 XSingle enthalpy sensors 2 X X Differential enthalpy sensors 2 XWall or duct mounted CO2 sensor 2 XUnit mounted CO2 sensor 2 X 4-in filter track assembly X
Gas Heat
Propane conversion kit XStainless steel heat exchanger X High altitude conversion kit XFlue discharge deflector X
Indoor Motor & Drive
Multiple motor and drive packages X Staged Air Vol (SAV™) system w/VFD controller (2-stage cool only with electrical mechanical and RTU Open controls) X
Display Kit for SAV™ system with VFD X
Low Ambient Control Winter start kit 3 XMotormaster® head pressure controller to -20°F (-29°C) 3 X
Power Options
Convenience outlet (powered) X Convenience outlet (unpowered): 15 amp factory-installed,20 amp field-installed X X
Non-fused disconnect 4 X
Roof Curbs Roof curb 14-in. (356 mm) XRoof curb 24-in. (610 mm) XAdapter curb (Adapts to models: DP/DR/HJ/TM/TJ) 5 X
Options and accessories
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Factory-installed optionsEconomizer (dry-bulb or enthalpy) Economizers can reduce operating costs. They bring infresh, outside air for ventilation; and provide cool outsideair to cool your building. This also is the preferred methodof low ambient cooling. When coupled to CO2 sensors,economizers can limit the ventilation air to only thatamount required. Economizers are available, installed and tested by the fac-tory, with either enthalpy or temperature dry-bulb inputs.There are also models for electro-mechanical, direct digitalcontrollers and single speed fan or 2-speed indoor fanmotors. Additional sensors are available as accessories tooptimize the economizer. Economizers include gravity controlled barometric reliefthat helps equalize building pressure and ambient air pres-sures. This can be a cost effective solution to prevent build-ing pressurization. Economizers are available in ultra lowleak and low leak versions. CO2 sensor The CO2 sensor works with the economizer to intake onlythe correct amount of outside air for ventilation. As occu-pants fill your building, the CO2 sensor detects their pres-ence through increasing CO2 levels, and opens theeconomizer appropriately. When the occupants leave, the CO2 levels decrease, andthe sensor appropriately closes the economizer. This intel-ligent control of the ventilation air, called Demand Con-trolled Ventilation (DCV), reduces the overall load on therooftop, saving money. Smoke detectors Trust the experts. Smoke detectors make your applicationsafer and your job easier. Carrier smoke detectors immedi-ately shut down the rooftop unit when smoke is detected.They are available, installed by the factory, for supply air,return air, or both. Louvered hail guards Sleek, louvered panels protect the condenser coil from haildamage, foreign objects, and incidental contact. Convenience outlet (powered or un-powered) Reduce service and/or installation costs by including a con-venience outlet in your specification. Carrier will install thisservice feature at our factory. Provides a convenient,15 amp, 115v GFCI receptacle with “Wet in Use” cover.The “powered” option allows the installer to power the out-let from the line side of the disconnect side as required bycode. The “un-powered” option is to be powered from aseparate (non-unit) 115/120v power source. The unpow-ered convenience outlet is available as a 15 amp factory-installed option or a 20 amp field-installed accessory.The 20 amp unpowered convenience outlet kit provides aflexible installation method which allows code compliancefor height requirements of the GFCI outlet from the fin-ished roof surface as well as the capability to relocate theoutlet to a more convenient location, if necessary.
Non-fused disconnect This OSHA-compliant, factory-installed, safety switchallows a service technician to locally secure power to therooftop. When selecting a factory-installed non-fused disconnect,note they are sized for unit as ordered from the factory.The sizing of these does not accommodate any powerexhaust devices, etc. Power exhaust with barometric relief Superior internal building pressure control. This field-installed accessory or factory-installed option may elimi-nate the need for costly, external pressure control fans. PremierLink™ DDC controllerThis CCN controller regulates your rooftop’s performanceto tighter tolerances and expanded limits, as well as facili-tates zoning systems and digital accessories. It also unitesyour Carrier HVAC equipment together on one, coherentCCN network. The PremierLink controller can be factory-installed, or easily field-installed, but it is not available withSAV. Since SAV is required for units installed in the USA,PremierLink is not applicable.RTU Open protocol controller Connect the rooftop to an existing BAS without needingcomplicated translators or adapter modules using the RTUOpen controller. This new controller speaks the 4 mostcommon building automation system languages (BACnet1,Modbus2, N2, and LonWorks3). Use this controller whenyou have an existing BAS. Time guard II control circuit This accessory protects your compressor by preventingshort-cycling in the event of some other failure, preventsthe compressor from restarting for 30 seconds after stop-ping. Not required with PremierLink™controller, RTUOpen controller, or authorized commercial thermostats. Optional Humidi-MiZer® adaptive dehumidifi-cation system Carrier’s Humidi-MiZer adaptive dehumidification systemis an all-inclusive factory-installed option that can beordered with any WeatherMaker® 48TC17-28 rooftopunit equipped with Round Tube-Plate Fin (RTPF) coils.This system expands the envelope of operation of Carrier’sWeatherMaker rooftop products to provide unprecedentedflexibility to meet year round comfort conditions.The Humidi-MiZer adaptive dehumidification system has aunique dual operational mode setting. The Humidi-MiZersystem includes two new modes of operation. The WeatherMaker 48TC17-28 rooftop coupled with theHumidi-MiZer system is capable of operating in normaldesign cooling mode, subcooling mode, and hot gas reheatmode. Normal design cooling mode is when the unit willoperate under its normal sequence of operation by cyclingcompressors to maintain comfort conditions.
1. BACnet is a registered trademark of ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers).
2. Modbus is a registered trademark of Schneider Electric.3. LonWorks is a registered trademark of Echelon Corporation.
Options and accessories (cont)
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Subcooling mode will operate to satisfy part load type con-ditions when the space requires combined sensible and ahigher proportion of latent load control. Hot Gas Reheatmode will operate when outdoor temperatures diminishand the need for latent capacity is required for sole humid-ity control. Hot Gas Reheat mode will provide neutral airfor maximum dehumidification operation.Motorized 2-position damper The new Carrier 2-position, motorized outdoor air damperadmits up to 100% outside air. Using reliable, gear-driventechnology, the 2-position damper opens to allow ventila-tion air and closes when the rooftop stops, stoppingunwanted infiltration. Not for use with SAV models.Manual OA damper Manual outdoor air dampers are an economical way tobring in ventilation air. The dampers are available in 25%versions. Not for use with SAV models.Staged air volume (SAV™) indoor fan speed sys-tem with a variable frequency drive (VFD)Carrier’s Staged Air Volume (SAV) system saves energy andinstallation time by utilizing a Variable Frequency Drive(VFD) to automatically adjust the indoor fan motor speed insequence with the units cooling operation. Per ASHRAE90.1-2016 and IECC-2015 standards, during the first stageof cooling operation the VFD will adjust the fan motor toprovide 66% of the total cfm established for the unit. Whena call for the second stage of cooling is required, the VFDwill allow the total cfm for the unit established (100%).During the heating mode the VFD will allow total design cfm(100%) operation and during the ventilation mode the VFDwill allow operation to 66% of total cfm. Compared to single speed indoor fan motor systems,Carrier’s SAV system can save substantial energy, 25%+versus single speed indoor fan motor systems.
The VFD used in Carrier’s SAV system has soft start capa-bilities to slowly ramp up the speeds, thus eliminating anyhigh inrush air volume during initial start-up. It also hasinternal over current protection for the fan motor and afield-installed display kit that allows adjustment and indepth diagnostics of the VFD. This SAV system is available on models with 2-stage cool-ing operation with electrical mechanical or RTU Open,Multi Protocol controls. Both space sensor and conven-tional thermostats controls can be used to provide accuratecontrol in any application. The SAV system is very flexible for initial fan performanceset up and adjustment. The standard factory shipped VFDis preprogrammed to automatically stage the fan speedbetween the first and second stage of cooling. The unit fanperformance static pressure and cfm can be easily adjusted
using the traditional means of pulley adjustments. Theother means to adjust the unit static and cfm performanceis to utilize the field-installed display kit and adjust the fre-quency and voltage in the VFD to required performancerequirements. In either case, once set up, the VFD willautomatically adjust the speed between the cooling stageoperations. Motormaster® head pressure controller The Motormaster motor controller is a low ambient, headpressure controller kit that is designed to maintain theunit’s condenser head pressure during periods of low ambi-ent cooling operation. This device should be used as analternative to economizer free cooling when economizerusage is either not appropriate or desired. The Motormas-ter will either cycle the outdoor-fan motors or operatethem at reduced speed to maintain the unit operation,depending on the model. Optional stainless steel heat exchanger The stainless steel heat exchanger option provides thetubular heat exchanger be made out of a minimum20 gage type 409 stainless steel for applications where themixed air to the heat exchanger is expected to drop below45°F (7°C). Stainless steel may be specified on applicationswhere the presence of airborne contaminants require itsuse (applications such as paper mills) or in area with veryhigh outdoor humidity that may result in severe condensa-tion in the heat exchanger during cooling operation. Hinged access panelsAllows access to unit’s major components with specificallydesigned hinged access panels. Panels are: filter, controlbox, and fan motor. Alternate motors and drives Some applications need larger horsepower motors, someneed more airflow, and some need both. Regardless of thecase, your Carrier expert has a factory-installed combina-tion to meet your application. A wide selection of motorsand pulleys (drives) are available, factory-installed, to han-dle nearly any application. Thru-the-bottom connections Provisions for thru-the-bottom power connections arestandard. Condensate overflow switch (factory-installed option) This sensor and related controller monitors the condensatelevel in the drain pan and shuts down compression opera-tion when overflow conditions occur. It includes: • Indicator light — solid red (more than 10 seconds on
water contact — compressors disabled), blinking red(sensor disconnected)
• 10 second delay to break — eliminates nuisance tripsfrom splashing or waves in pan (sensor needs 10 sec-onds of constant water contact before tripping)
• Disables the compressor(s) operation when condensateplug is detected, but still allows fans to run for Economizer.
IMPORTANT: Data based on 0.10 ($/kWh) in anoffice application utilizing Carrier’s HAP 4.6 simula-tion software program.
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Field-installed accessoriesWinter start kit The winter start kit by Carrier extends the low ambientlimit of your rooftop to 25°F (–4°C). The kit bypasses thelow pressure switch, preventing nuisance tripping of thelow pressure switch. Other low ambient precautions maystill be prudent. Motormaster allows cooling operation down to –20°F(–29°C) ambient conditions.Propane heating Convert your gas heat rooftop from standard natural gasoperation to propane using this field-installed kit.
High altitude heating High altitudes have less oxygen, which means heatexchangers need less fuel. The new gas orifices in this field-installed kit make the necessary adjustment for high alti-tude applications. They restore the optimal fuel to air mix-ture and maintain healthy combustion at altitudes above2000 ft (610 m). Kits may not be required in all areas. Flue discharge deflector The flue discharge deflector is a useful accessory when fluegas recirculation is a concern. By venting the flue dischargeupwards, the deflector minimizes the chance for a neigh-boring unit to intake the flue exhaust.
OPTIONS AND ACCESSORIES — WEIGHT ADDERS
1 For Humidi-MiZer® System add Motormaster Controller.
2 Where available.
— Not available
BASE UNIT WITH OPTIONS ANDACCESSORIES (Weight Adders)
— — Do not operateCfm — Cubic feet per minute (supply air)EAT (db) — Entering Air Temperature (dry bulb)EAT (wb) — Entering Air Temperature (wet bulb)SHC — Sensible Heat Capacity (1000 Btuh) GrossTC — Total Capacity (1000 Btuh) Gross
— — Do not operateCfm — Cubic feet per minute (supply air)EAT (db) — Entering Air Temperature (dry bulb)EAT (wb) — Entering Air Temperature (wet bulb)SHC — Sensible Heat Capacity (1000 Btuh) GrossTC — Total Capacity (1000 Btuh) Gross
— — Do not operateCfm — Cubic feet per minute (supply air)EAT (db) — Entering Air Temperature (dry bulb)EAT (wb) — Entering Air Temperature (wet bulb)SHC — Sensible Heat Capacity (1000 Btuh) GrossTC — Total Capacity (1000 Btuh) Gross
— — Do not operateCfm — Cubic feet per minute (supply air)EAT (db) — Entering Air Temperature (dry bulb)EAT (wb) — Entering Air Temperature (wet bulb)SHC — Sensible Heat Capacity (1000 Btuh) GrossTC — Total Capacity (1000 Btuh) Gross
— — Do not operateCfm — Cubic feet per minute (supply air)EAT (db) — Entering Air Temperature (dry bulb)EAT (wb) — Entering Air Temperature (wet bulb)SHC — Sensible Heat Capacity (1000 Btuh) GrossTC — Total Capacity (1000 Btuh) Gross
Low Speed 230,460,575V Med Speed 230,460,575V High Speed 230,460,575V
Power Exhaust Fan Performance
44
GENERAL FAN PERFORMANCE NOTES1. Interpolation is permissible. Do not extrapolate.2. External static pressure is the static pressure difference between the return duct and the supply duct plus the static
pressure caused by any factory-installed options (FIOPs) or accessories.3. Tabular data accounts for pressure loss due to clean filters, high gas heat, unit casing, and wet coils. Factory options
and accessories may add static pressure losses. Selection software is available, through your salesperson, to help youselect the best motor/drive combination for your application.
4. The fan performance tables offer motor/drive recommendations. In cases when two motor/drive combinations wouldwork, Carrier recommends the lower horsepower option.
5. For information on the electrical properties of Carrier motors, please see the Electrical information section of thisbook. For more information on the performance limits of Carrier motors, see the application data section of thisbook.
Applicable for Electrical Data Tables on pages 50-57
LEGEND
NOTES1. In compliance with NEC requirements for multi-motor and combi-
nation load equipment (refer to NEC Articles 430 and 440), theovercurrent protective device for the unit shall be fuse or HACRbreaker. Canadian units may be fuse or circuit breaker.
2. For 208/230 v units, where one value is shown it is the same foreither 208 or 230 volts.
3. Unbalanced 3-Phase Supply VoltageNever operate a motor where a phase imbalance in supply voltageis greater than 2%. Use the following formula to determine the per-centage of voltage imbalance.
Example: Supply voltage is 230-3-60
Determine maximum deviation from average voltage.
(AB) 227-224 = 3 v
(BC) 231-227 = 4 v
(AC) 227-226 = 1 v
Maximum deviation is 4 v.
Determine percent of voltage imbalance.
This amount of phase imbalance is satisfactory as it is below the maxi-mum allowable 2%.
NOTE: The 2-speed motors are the same efficiency level as the singlespeed motors.
TYPICAL POWER WIRING DIAGRAM, 48TC 17-30 460V SHOWN
Typical wiring diagrams
59
ELECTRO-MECHANICAL CONTROL WIRING DIAGRAM 48TC 17-30
60
ELECTRO-MECHANICAL CONTROL WIRING DIAGRAM 48TC 17-30 WITH OPTIONAL HUMIDI-MIZER® SYSTEM
Typical wiring diagrams (cont)
61
The sequence below describes the sequence of operationfor an electro-mechanical unit with and without a factory-installed EconoMi$er® IV and X (called “economizer” inthis sequence). For information regarding a direct digitalcontroller, see the start-up, operations, and troubleshoot-ing manual for the applicable controller.Electro-mechanical units with no economizerCooling (Single speed indoor fan motor)When the thermostat calls for cooling, terminals G and Y1are energized. As a result, the indoor-fan contactor (IFC)and the compressor contactor (C1) are energized, causingthe indoor-air motor (IFM), compressor #1, and outdoorfan to start. If the unit has 2 stages of cooling, the thermo-stat will additionally energize Y2. The Y2 signal will ener-gize compressor contactor #2 (C2), causing compressor#2 to start. Regardless of the number of stages, the out-door fan motor runs continuously while unit is cooling.Cooling (2-speed indoor fan motor) Per ASHRAE 90.1-2016, and IECC-2015 standards,during the first stage of cooling operation the VFD willadjust the fan motor to provide 66% of the total cfm estab-lished for the unit. When a call for the second stage ofcooling is required, the VFD will allow the total cfm for theunit established (100%). This is standard on all modelsinstalled in the U.S. to meet U.S. Department of Energy -2018 IEER efficiency rating.Heating WeatherMaker® (48TC) units have 2 stages of gas heat.When the thermostat calls for heating, power is sent to Won the Integrated Gas Controller (IGC) board. An LED (light-emitting diode) on the IGC board turns on and remains onduring normal operation. A check is made to ensure that theroll-out switch and limit switch are closed. If the check wassuccessful, the induced-draft motor is energized, and whenits speed is satisfactory, as proven by the flue gas pressureswitch, the ignition activation period begins. The burnerswill ignite within 5 seconds. If the burners do not light, thereis a 22 second delay before another 5 second attempt. Thissequence is repeated for 15 minutes or until the burnerslight. If, after the 15 minutes, the burners still have not lit,heating is locked out. To reset the control, break 24-v powerto the thermostat. When ignition occurs, the IGC board will continue to moni-tor the condition of the roll-out switch, the limit switches,the flue gas pressure switch, as well as the flame sensor.Forty-five seconds after ignition occurs, assuming the unitis controlled through a room thermostat set for fan auto,the indoor-fan motor will energize (and the outdoor-airdampers will open to their minimum position). If, for somereason, the over-temperature limit opens prior to the startof the indoor fan blower, the unit will shorten the45 second delay to 5 seconds less than the time from initi-ation of heat to when the limit tripped. Gas will not beinterrupted to the burners and heating will continue. Oncethe fan-on delay has been modified, it will not change backto 45 seconds until power is reset to the control. On unitswith 2 stages of heat, when additional heat is required, W2closes and initiates power to the second stage of the maingas valve. When the thermostat is satisfied, W1 and W2
open and the gas valve closes, interrupting the flow of gasto the main burners. If the call for W1 lasted less than 1 minute, the heatingcycle will not terminate until 1 minute after W1 becameactive. If the unit is controlled through a room thermostatset for fan auto, the indoor-fan motor will continue to oper-ate for an additional 45 seconds then stop. If the over-tem-perature limit opens after the indoor motor is stopped, butwithin 10 minutes of W1 becoming inactive, on the nextcycle the time will be extended by 15 seconds. The maxi-mum delay is 3 minutes. Once modified, the fan off delaywill not change back to 45 seconds unless power is reset tothe control. A LED indicator is provided on the IGC tomonitor operation.Electro-mechanical units with an economizerCoolingWhen free cooling is not available, the compressors will becontrolled by the zone thermostat. When free cooling isavailable, the outdoor-air damper is modulated by theEconoMi$er IV and X control to provide a 50°F (10°C) to55°F (13°C) mixed-air temperature into the zone. As themixed air temperature fluctuates above 55°F (13°C) orbelow 50°F (10°C) dampers will be modulated (open orclose) to bring the mixed-air temperature back within con-trol. If mechanical cooling is utilized with free cooling, theoutdoor-air damper will maintain its current position at thetime the compressor is started. If the increase in coolingcapacity causes the mixed-air temperature to drop below45°F (7°C), then the outdoor-air damper position will bedecreased to the minimum position. If the mixed-air tem-perature continues to fall, the outdoor-air damper willclose. Control returns to normal once the mixed-air tem-perature rises above 48°F (9°C). The power exhaust fanswill be energized and de-energized, if installed, as the out-door-air damper opens and closes. If field-installed accessory CO2 sensors are connected tothe EconoMi$er IV and X control, a demand controlledventilation strategy will begin to operate. As the CO2 levelin the zone increases above the CO2 setpoint, the mini-mum position of the damper will be increased proportion-ally. As the CO2 level decreases because of the increase infresh air, the outdoor-air damper will be proportionallyclosed. For EconoMi$er IV and X operation, there must bea thermostat call for the fan (G). If the unit is occupied andthe fan is on, the damper will operate at minimum posi-tion. Otherwise, the damper will be closed.When the EconoMi$er IV and X control is in the occupiedmode and a call for cooling exists (Y1 on the thermostat),the control will first check for indoor fan operation. If thefan is not on, then cooling will not be activated. If the fan ison, then the control will open the EconoMi$er IV anddamper to the minimum position.On the initial power to the EconoMi$er IV and X control, itwill take the damper up to 21/2 minutes before it begins toposition itself. After the initial power-up, further changes indamper position can take up to 30 seconds to initiate.Damper movement from full closed to full open (or viceversa) will take between 11/2 and 21/2 minutes. If freecooling can be used as determined from the appropriatechangeover command (switch, dry bulb, enthalpy curve,
Sequence of operation
62
differential dry bulb, or differential enthalpy), then the con-trol will modulate the dampers open to maintain the mixed-air temperature setpoint at 50°F (10°C) to 55°F (13°C). If there is a further demand for cooling, then cooling sec-ond stage - Y2 is energized, and then the control will bringon compressor stage 1 to maintain the mixed-air tempera-ture setpoint. The EconoMi$er® IV and X damper will beopen at maximum position. EconoMi$er IV and X opera-tion is limited to a single compressor.2-Speed Note: When operating in ventilation mode only,the indoor fan motor will automatically adjust to 66% ofthe total cfm established.Heating The sequence of operation for the heating is the same asan electro-mechanical unit with no economizer. The onlydifference is how the economizer acts. The economizer willstay at the Economizer Minimum Position while the evapo-rator fan is operating. The outdoor-air damper is closedwhen the indoor fan is not operating. Refer to Service andMaintenance Manual for further details. Optional Humidi-MiZer® dehumidification system Units with the factory equipped Humidi-MiZer® option arecapable of providing multiple modes of improved dehumid-ification as a variation of the normal cooling cycle. The
Humidi-MiZer option includes additional valves in the liquidline and discharge line of each refrigerant circuit, a smallreheat condenser coil downstream of the evaporator, andMotormaster variable-speed control of some or all outdoorfans. Operation of the revised refrigerant circuit for eachmode is described below. The Humidi-MiZer system provides three sub-modes ofoperation: Cool, Reheat1, and Reheat2. • Cool mode - provides a normal ratio of Sensible and
Latent Cooling effect from the evaporator coil. • Reheat1 - provides increased Latent Cooling while
slightly reducing the Sensible Cooling effect. • Reheat2 - provides normal Latent Cooling but with null
or minimum Sensible Cooling effect delivered to thespace.
The Reheat1 and Reheat2 modes are a variable when theunit is not in a Heating mode and when the Low AmbientLockout switch is closed.RTU Open controller (factory option)For details on operating 48TC units equipped with the fac-tory-installed RTU Open option, refer to Factory InstalledOption RTU Open Multi-Protocol Controller Controls,Start-Up, Operation and Troubleshooting.
Sequence of operation (cont)
63
NORMAL COOLING MODE — HUMIDI-MIZER® SYSTEM
SUBCOOLING MODE (REHEAT 1) — HUMIDI-MIZER® SYSTEM
SUBCOOLING MODE (REHEAT 2) — HUMIDI-MIZER® SYSTEM
CONDENSER COIL
HUMIDIMIZER COIL
EVAPORATOR COIL
COMPRESSOR COMPRESSOR
OUTDOOR AIR
RDV1VALVE
LDV1VALVE
OUTDOOR AIR
RDV2VALVE
LDV2VALVE
TXVMETERINGDEVICE
TXVMETERING
DEVICE
= CLOSED VALVE
= OPEN VALVE
= 3-WAY VALVE
INDOOR LEAVING AIR
INDOOR ENTERING AIR
CONDENSER COILCIR 1 CIR 2
CIR 1 CIR 2
CONDENSER COIL
HUMIDIMIZER COIL
EVAPORATOR COIL
COMPRESSOR COMPRESSOR
OUTDOOR AIR
RDV1VALVE
LDV1VALVE
OUTDOOR AIR
RDV2VALVE
LDV2VALVE
TXVMETERINGDEVICE
TXVMETERING
DEVICE
= CLOSED VALVE
= OPEN VALVE
= 3-WAY VALVE
INDOOR LEAVING AIR
INDOOR ENTERING AIR
CONDENSER COILCIR 1 CIR 2
CIR 1 CIR 2
CONDENSER COIL
HUMIDIMIZER COIL
EVAPORATOR COIL
COMPRESSOR COMPRESSOR
OUTDOOR AIR
RDV1VALVE
LDV1VALVE
OUTDOOR AIR
RDV2VALVE
LDV2VALVE
TXVMETERINGDEVICE
TXVMETERING
DEVICE
= CLOSED VALVE
= OPEN VALVE
= 3-WAY VALVE
INDOOR LEAVING AIR
INDOOR ENTERING AIR
CONDENSER COILCIR 1 CIR 2
CIR 1 CIR 2
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Min operating ambient temp (cooling)In mechanical cooling mode, your Carrier rooftop unit cansafely operate down to an outdoor ambient temperature of30°F (–1°C). It is possible to provide cooling at lower out-door ambient temperatures by using less outside air, econo-mizers, and/or accessory low ambient kits.Max operating ambient temp (cooling)The maximum operating ambient temperature for coolingmode is 115°F (46°C). While cooling operation above115°F (46°C) may be possible, it could cause either areduction in performance, reliability, or a protective actionby the unit’s internal safety devices.Min mixed air temp (heating)Using the factory settings, the minimum temperatures forthe mixed air (the combined temperature of the warmreturn air and the cold outdoor air) entering the dimpled,gas heat exchangers are:
Operating at lower mixed-air temperatures may be possi-ble, if a field-supplied, outdoor air thermostat initiates bothheat stages when the temperature is less than the mini-mum temperatures listed above. Please contact your localCarrier representative for assistance.Min and max airflow (heating and cooling)To maintain safe and reliable operation of your rooftop,operate within the heating airflow limits during heatingmode and cooling airflow limits during cooling mode.Operating above the max may cause blow-off, undesiredairflow noise, or airflow related problems with the rooftopunit. Operating below the min may cause problems withcoil freeze-up and unsafe heating operation. For properminimum and maximum CFM values see Minimum - Maxi-mum Airflow Ratings - Natural Gas and Propane table onpage 6.Heating-to-cooling changeoverYour unit will automatically change from heating to coolingmode when using a thermostat with an auto-change-overfeature.AirflowAll units are draw-through in cooling mode and blow-through in heating mode. Outdoor air application strategies Economizers reduce operating expenses and compressorrun time by providing a free source of cooling and a meansof ventilation to match application changing needs. In fact,they should be considered for most applications. Also, con-sider the various economizer control methods and theirbenefits, as well as sensors required to accomplish yourapplication goals. Please contact your local Carrier repre-sentative for assistance.
Motor limits, break horsepower (BHP)Due to internal design of Carrier units, the air path, andspecially designed motors, the full horsepower (maximumcontinuous BHP) band, as listed in Physical Data TableCooling, can be used with the utmost confidence. There isno need for extra safety factors, as Carrier motors aredesigned and rigorously tested to use the entire, listed BHPrange without either nuisance tripping or premature motorfailure.Propane heatingPropane has different physical qualities than natural gas.As a result, propane requires different fuel to air mixture.To optimize the fuel/air mixture for propane, Carrier sellsdifferent burner orifices in an easy to install accessory kit.To select the correct burner orifices or determine the heatcapacity for an propane application, use either the selec-tion software, or the unit’s service manual.High altitude heatingHigh altitudes have less oxygen, which affects the fuel/airmixture in heat exchangers. In order to maintain a properfuel/air mixture, heat exchangers operating in altitudesabove 2000 ft (610 m) require different orifices. To selectthe correct burner orifices or determine the heat capacityfor a high altitude application, use either the selection soft-ware, or the unit’s service manual.High altitudes have less oxygen, which means heatexchangers need less fuel. The new gas orifices in this field-installed kit make the necessary adjustment for high alti-tude applications. They significantly improve fuel to airmixture and maintain healthy combustion on altitudesabove 2000 ft (610 m).NOTE: Typical natural gas heating value ranges from 975to 1050 Btu/ft3 at sea level nationally. The heating valuegoes down approximately 1.7% per every thousand feetelevation. Standard factory orifices can typically be used upto 2000 ft (610 m) elevation without any operationalissues.Sizing a rooftopBigger isn’t necessarily better. While an air conditionerneeds to have enough capacity to meet the design loads, itdoesn’t need excess capacity. In fact, excess capacity typi-cally results in very poor part load performance andhumidity control.Using higher design temperatures than ASHRAE recom-mends for your location, adding “safety factors” to the cal-culated load, are all signs of oversizing air conditioners.Oversizing the air conditioner leads to poor humidity con-trol, reduced efficiency, higher utility bills, larger indoortemperature swings, excessive noise, and increased wearand tear on the air conditioner. Rather than oversizing anair conditioner, engineers should “right-size” or evenslightly undersize air conditioners. Correctly sizing an airconditioner controls humidity better; promotes efficiency;reduces utility bills; extends equipment life, and maintainseven, comfortable temperatures. Please contact your localCarrier representative for assistance.
Application data
65
Low ambient applicationsThe optional Carrier economizer can adequately cool yourspace by bringing in fresh, cool outside air. In fact, when soequipped, accessory low-ambient kit may not be necessary.In low ambient conditions, unless the outdoor air is exces-sively humid or contaminated, economizer-based “freecooling” is the preferred less costly and energy consciousmethod. In low ambient applications where outside airmight not be desired (such as contaminated or excessivelyhumid outdoor environments), your Carrier rooftop canoperate to ambient temperatures down to –20°F (–29°C)using the recommended accessory Motormaster low ambi-ent controller or down to 25°F (–4°C) with the field-installed Winter Start Package.Staged air volume (SAV™) with variable fre-quency drive (VFD)Carrier’s Staged Air Volume (SAV™) system utilizes a Vari-able Frequency Drive (VFD) to automatically adjust theindoor fan motor speed in sequence with the units coolingoperation. Per ASHRAE 90.1-2016 standard, during thefirst stage of cooling operation the VFD will adjust the fanmotor to provide 66% of the total cfm established for theunit. When a call for the second stage of cooling isrequired, the VFD will allow the total cfm for the unit estab-lished (100%). During the heating mode, the VFD willallow total design cfm (100%) operation and during theventilation mode the VFD will allow operation to 66% oftotal cfm.
The VFD used in Carrier’s SAV system has soft start capa-bilities to slowly ramp up the speeds, thus eliminating anyhigh inrush air volume during initial start-up. It also hasinternal over current protection for the fan motor and afield-installed display kit that allows adjustment and indepth diagnostics of the VFD.This SAV system is available on models with 2-stage cool-ing operation with electro-mechanical or RTU Open (multiProtocol) controls. Both space sensor and conventionalthermostats controls can be used to provide accurate con-trol in any application.The SAV system is very flexible for initial fan performanceset up and adjustment. The standard factory shipped VFDis pre-programmed to automatically stage the fan speedbetween the first and second stage of cooling. The unit fanperformance static pressure and cfm can be easily adjustedusing the traditional means of pulley adjustments. Theother means to adjust the unit static and cfm performanceis to utilize the field-installed display module and adjust thefrequency and voltage in the VFD to required performancerequirements. In either case, once set up the VFD will auto-matically adjust the speed between the cooling stageoperation.Application/selection option Selection software by Carrier saves time by performingmany of the steps above. Contact your Carrier sales repre-sentative for assistance.
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Note about this specification: These specifications are written in“Masterformat” as published by the Construction Specification Institute.Please feel free to copy this specification directly into your buildingspec.
A. (23 07 16.13.A.) Evaporator fan compartment:1. Interior cabinet surfaces shall be insulated with a
minimum 1/2-in. thick, minimum 1 1/2-lb den-sity, flexible fiberglass insulation bonded with aphenolic binder, neoprene coated on the air side.
2. Insulation and adhesive shall meet NFPA 90Arequirements for flame spread and smokegeneration.
3. Unit internal insulation linings shall be resistantto mold growth in accordance with “moldgrowth and humidity” test in ASTM C1338,G21, and UL 181 or comparable testmethod. Air stream surfaces shall be evalu-ated in accordance with the “Erosion Test” inUL 181, as part of ASTM C1071.
B. (23 07 16.13.B.) Gas heat compartment:1. Aluminum foil-faced fiberglass insulation shall
be used.2. Insulation and adhesive shall meet NFPA 90A
requirements for flame spread and smokegeneration.
Part 3 — (23 09 23) Instrumentation and control devices for HVAC3.01 (23 09 12.13) Sensors and Transmitters
A. (23 09 12.13.A.) Thermostats:1. Thermostat must
a. energize both “W” and “G” when callingfor heat.
b. have capability to energize 2 differentstages of cooling, and 2 different stages ofheating.
c. include capability for occupancy scheduling.
Part 4 — (23 09 23) Direct-digital control system for HVAC4.01 (23 09 23.13) Decentralized, Rooftop Units:
A. (23 09 23.13.A.) PremierLink™ controller (notcompatible with SAV models):
1. Shall be ASHRAE 62 compliant.2. Shall accept 18-32 VAC input power.3. Shall have an operating temperature range from
–40°F (–40°C) to 158°F (70°C), 10% to 95%RH (non-condensing).
4. Shall include an integrated economizer controllerto support an economizer with 4 to 20 mA actua-tor input and no microprocessor controller.
5. Controller shall accept the following inputs:space temperature, setpoint adjustment, out-door air temperature, indoor air quality, out-door air quality, indoor relative humidity,compressor lock-out, fire shutdown, enthalpy,fan status, remote time clock/door switch.
6. Shall accept a CO2 sensor in the conditionedspace, and be Demand Controlled Ventilation(DCV) ready.
7. Shall provide the following outputs: econo-mizer, fan, cooling stage 1, cooling stage 2,heat stage 1, heat stage 2, heat stage 3/exhaust/reversing valve/dehumidify/occupied.
8. Unit shall provide surge protection for the con-troller through a circuit breaker.
9. Shall be Internet capable, and communicate ata Baud rate of 38.4K or faster.
10. Shall have an LED display independentlyshowing the status of activity on the communi-cation bus, and processor operation.
11. Shall include an EIA-485 protocol communi-cation port, an access port for connection ofeither a computer or a Carrier technician tool,an EIA-485 port for network communicationto intelligent space sensors and displays, anda port to connect an optional LonWorks1 plug-in communications card.
12. Shall have built-in Carrier Comfort Network®
(CCN) protocol, and be compatible with otherCCN devices, including ComfortVIEW controllers.
13. Shall have built-in support for Carrier techni-cian tool.
14. Software upgrades will be accomplished bylocal download. Software upgrades throughchip replacements are not allowed.
15. Shall be shock resistant in all planes to 5Gpeak, 11ms during operation, and 100G peak,11ms during storage.
16. Shall be vibration resistant in all planes to1.5G at 20-300 Hz.
1. LonWorks is a registered trademark of Echelon Corporation.
Guide specifications
67
17. Shall support a bus length of 4000 ft (1219 m)max, 60 devices per 1000 ft (305 m) section, and1 RS-485 repeater per 1000 ft (305 m) sections.
B. (23 09 23.13.B.) RTU Open mult i -protocol,direct digital controller:
1. Shall be ASHRAE 62 compliant.2. RTU Open controls meets California Title 24
Section 120.2i, ASHRAE 90.1-2016 andIECC1-2015 Fault Detection and Diagnostic(FDD) requirements.
3. Shall accept 18-30VAC, 50-60 Hz, and con-sume 15VA or less power.
4. Shall have an operating temperature rangefrom –40°F (–40°C) to 130°F (54°C), 10%to 90% RH (non-condensing).
5. Shall include built-in protocol for BACnet2(MS/TP and PTP modes), Modbus3 (RTU andASCII), Johnson N2 and LonWorks. Lon-Works Echelon processor required for all Lonapplications shall be contained in separatecommunication board.
6. Shall allow access of up to 62 network vari-ables (SNVT). Shall be compatible with allopen controllers.
7. Baud rate controller shall be selectable using adip switch.
8. Shall have an LED display independentlyshowing the status of serial communication,running, errors, power, all digital outputs, andall analog inputs.
9. Shall accept the following inputs: space tem-perature, setpoint adjustment, outdoor airtemperature, indoor air quality, outdoor airquality, compressor lock-out, fire shutdown,enthalpy switch, and fan status/filter status/humidity/remote occupancy.
10. Shall provide the following outputs: econo-mizer, fan, cooling stage 1, cooling stage 2,heat stage 1, heat stage 2, heat stage 3/exhaust/reversing valve.
11. Shall have built-in surge protection circuitrythrough solid-state polyswitches. Polyswitchesshall be used on incoming power and networkconnections. Polyswitches will return to normalwhen the “trip” condition clears.
12. Shall have a battery backup capable of aminimum of 10,000 hours of data and timeclock retention during power outages.
13. Shall have built-in support for Carrier techni-cian tool.
14. Shall include an EIA-485 protocol communi-cation port, an access port for connection ofeither a computer or a Carrier technician tool,
an EIA-485 port for network communicationto intelligent space sensors and displays, anda port to connect an optional LonWorks com-munications card.
15. Software upgrades will be accomplished byeither local or remote download. No softwareupgrades through chip replacements areallowed.
Part 5 — (23 09 33) Electric and electronic control system for HVAC5.01 (23 09 33.13) Decentralized, rooftop units
A. (23 09 33.13.A.) General:1. Shall be complete with self-contained low-volt-
age control circuit protected by a resettable cir-cuit breaker on the 24-v transformer side.Transformer shall have 75VA capability.
2. Shall utilize color-coded wiring.3. Shall include a central control terminal board
to conveniently and safely provide connec-tion points for vital control functions such as:smoke detectors, phase monitor, gas control-ler, economizer, thermostat, DDC controloptions, and low and high pressure switches.
4. The heat exchanger shall be controlled by anintegrated gas controller (IGC) microprocessor.See heat exchanger section of this specification.
5. Unit shall include a minimum of one 8-pinscrew terminal connection board for connec-tion of control wiring.
B. (23 09 33.13.B.) Safeties:1. Compressor over-temperature, over-current.
High internal pressure differential.2. Low-pressure switch:
a. Units shall have different sized connectorsfor the circuit 1 and circuit 2 low and highpressure switches. They shall physically pre-vent the cross-wiring of the safety switchesbetween circuits 1 and 2.
b. Low-pressure switch shall use different colorwire than the high-pressure switch. Thepurpose is to assist the installer and servicetechnician to correctly wire and or trouble-shoot the rooftop unit.
3. High-pressure switch:a. Units shall have different sized connectors
for the circuit 1 and circuit 2 low and high-pressure switches. They shall physically pre-vent the cross-wiring of the safety switchesbetween circuits 1 and 2.
b. High-pressure switch shall use differentcolor wire than the low-pressure switch.The purpose is to assist the installer andservice technician to correctly wire and ortroubleshoot the rooftop unit.
4. Automatic reset, motor thermal overload protector.
1. IECC is a registered trademark of International Code Council, Inc.2. BACnet is a registered trademark of ASHRAE (American Society of
Heating, Refrigerating and Air-Conditioning Engineers). 3. Modbus is a registered trademark of Schneider Electric.
68
5. Heating section shall be provided with the following minimum protections:a. High-temperature limit switches.b. Induced draft motor speed sensor.c. Flame roll-out switch.d. Flame proving controls.
Part 6 — (23 09 93) Sequence of operations for HVAC controls6.01 (23 09 93 13) Decentralized, Rooftop Units:
A. (23 09 93 13.A.) INSERT SEQUENCE OF OPERATION
Part 7 — (23 40 13) Panel air filters7.01 (23 40 13.13) Decentralized rooftop units:
A. (23 40.13.13.A.) Standard filter section:1. Shall consist of factory-installed, low velocity,
disposable 2-in. thick fiberglass filters of com-mercially available sizes.
2. Unit shall use only one filter size. Multiple sizesare not acceptable.
3. Filters shall be accessible through a dedicated,weather tight access panel.
4. 4-in. filter capabilities shall be capable withpre-engineered and approved Carrier filtertrack field-installed accessory. This kit requiresfield furnished filters.
Part 8 — (23 81 19) Self-contained air conditioners8.01 (23 81 19.13) Medium-Capacity Self-Contained Air
1. Outdoor, rooftop mounted, electrically con-trolled, heating and cooling unit utilizing a fullyhermetic scroll compressor(s) for cooling dutyand gas combustion for heating duty.
2. Factory assembled, single-piece heating andcooling rooftop unit. Contained within theunit enclosure shall be all factory wiring, pip-ing, controls, and special features requiredprior to field start-up.
3. Unit shall use Puron® refrigerant.4. Unit shall be installed in accordance with the
manufacturer’s instructions.5. Unit must be selected and installed in compli-
ance with local, state, and federal codes.B. (23 81 19.13.B.) Quality Assurance
1. Unit meets Department of Energy-2018,ASHRAE 90.1-2016 and IECC-2015 min-imum efficiency requirements.
2. Unit shall be rated in accordance with AHRIStandard 340/360.
3. Unit shall be designed to conform to ASHRAE15.
4. Unit shall be ETL-tested and certified in accor-dance with ANSI Z21.47 Standards and ETL-
listed and certified under Canadian standardsas a total package for safety requirements.
5. Insulation and adhesive shall meet NFPA 90Arequirements for flame spread and smokegeneration.
6. Unit internal insulation linings shall be resistantto mold growth in accordance with “moldgrowth and humidity” test in ASTM C1338,G21, and UL 181 or comparable testmethod. Air stream surfaces shall be evalu-ated in accordance with the “Erosion Test” inUL 181, as part of ASTM C1071.
7. Unit casing shall be capable of withstanding500 hour salt spray exposure per ASTM B117(scribed specimen).
8. Roof curb shall be designed to conform toNRCA Standards.
9. Unit shall be subjected to a completely auto-mated run test on the assembly line. The datafor each unit will be stored at the factory, andmust be available upon request.
10. Unit shall be designed in accordance with ULStandard 1995, ETL listed including tested towithstand rain.
11. Unit shall be constructed to prevent intrusionof snow and tested to prevent snow intrusioninto the control box up to 40 mph.
12. Unit shake tested to assurance level 1, ASTMD4169 to ensure shipping reliability.
13. High Efficiency Motors listed shall meet sec-tion 313 of the Energy Independence andSecurity Act of 2007 (EISA 2007).
C. (23 81 19.13.C.) Delivery, storage, and handling:1. Unit shall be stored and handled per manufac-
turer’s recommendations.2. Lifted by crane requires either shipping top
panel or spreader bars.3. Unit shall only be stored or positioned in the
upright position. D. (23 81 19.13.D.) Project conditions:
1. As specified in the contract.E. (23 81 19.13.E.) Operating characteristics:
1. Unit shall be capable of starting and runningat 115 F (46 C) ambient outdoor temperature,meeting maximum load criteria of AHRI Stan-dard 340/360 at ± 10% voltage.
2. Compressor with standard controls shall becapable of operation down to 30°F (–1°C), ambi-ent outdoor temperatures. Accessory winter startkit is necessary if mechanically cooling at ambi-ent temperatures below 30°F (–1°C).
3. Unit shall discharge supply air vertically asshown on contract drawings.
4. Unit shall be factory configured and orderedfor vertical supply and return configurations.
Guide specifications (cont)
69
5. Unit shall be factory furnished for vertical con-figuration. No field conversion is required.
F. (23 81 19.13.F.) Electrical Requirements:1. Main power supply voltage, phase, and frequency
must match those required by the manufacturer.G. (23 81 19.13.G.) Unit cabinet:
1. Unit cabinet shall be constructed of galva-nized steel, and shall be bonderized andcoated with a pre-painted baked enamel finishon all externally exposed surfaces.
3. Evaporator fan compartment interior cabinetinsulation shall conform to AHRI Standard340/360 minimum exterior sweat criteria.Interior surfaces shall be insulated with a min-imum 1/2-in. thick, 1- lb density, flexible fiber-glass insulation, neoprene coated on the airside. Aluminum foil-faced fiberglass insulationshall be used in the gas heat compartment.
4. Unit internal insulation linings shall be resistantto mold growth in accordance with “moldgrowth and humidity” test in ASTM C1338,G21, and UL 181 or comparable testmethod. Air stream surfaces shall be evalu-ated in accordance with the “Erosion Test” inUL 181, as part of ASTM C1071.
5. Base of unit shall have a minimum of fourlocations for thru-the-base gas and electricalconnections standard. Both gas and electricconnections shall be internal to the cabinet toprotect from environmental issues.
6. Base rail:a. Unit shall have base rails on a minimum of
2 sides.b. Holes shall be provided in the base rails for
rigging shackles to facilitate maneuveringand overhead rigging.
c. Holes shall be provided in the base rail formoving the rooftop by fork truck.
d. Base rail shall be a minimum of 16-gagethickness.
7. Condensate pan and connections:a. Shall be a sloped condensate drain pan
made of a non-corrosive material.b. Shall comply with ASHRAE Standard 62.c. Shall use a 3/4-in.-14 NPT drain connec-
tion, through the side of the drain pan.Connection shall be made per manufac-turer’s recommendations.
8. Top panel:a. Shall be a multi-piece top panel linked with
water tight flanges and locking systems.
9. Gas connections:a. All gas piping connecting to unit gas valve
shall enter the unit cabinet at a single loca-tion on side of unit (vertical plane).
b. Thru-the-base capability:1.) Standard unit shall have a thru-the-base
gas-line location using a raised,embossed portion of the unit basepan.
2.) Thru-the-base provisions / connectionsare available as standard with every unit.When bottom connections are required,field furnished couplings are required.
3.) No basepan penetration, other thanthose authorized by the manufacturer, ispermitted.
10. Electrical connections:a. All unit power wiring shall enter unit cabinet at
a single, factory-prepared, knockout location.b. Thru-the-base capability:
1.) Thru-the-base provisions/connections areavailable as standard with every unit.When bottom connections are required,field furnished couplings are required.
2.) No basepan penetration, other thanthose authorized by the manufacturer, ispermitted.
11. Component access panels (standard):a. Cabinet panels shall be easily removable for
servicing.b. Unit shall have one factory-installed, remov-
able, filter access panel.c. Panels covering control box and filter shall
have molded composite handles while theblower access door shall have an integratedflange for easy removal.
d. Handles shall be UV modified, composite.They shall be permanently attached, andrecessed into the panel.
e. Screws on the vertical portion of all remov-able access panel shall engage into heatresistant, molded composite collars.
f. Collars shall be removable and easilyreplaceable using manufacturer recom-mended parts.
H. (23 81 19.13.H.) Gas heat:1. General:
a. Heat exchanger shall be an induced draftdesign. Positive pressure heat exchangerdesigns shall not be allowed.
b. Shall incorporate a direct-spark ignition sys-tem and redundant main gas valve.
c. Gas supply pressure at the inlet to the roof-top unit gas valve must match that requiredby the manufacturer.
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2. The heat exchanger shall be controlled by anintegrated gas controller (IGC) microprocessor:a. IGC board shall notify users of fault using
an LED (light-emitting diode).b. IGC board shall contain algorithms that mod-
ify evaporator-fan operation to prevent futurecycling on high temperature limit switch.
c. Unit shall be equipped with anti-cycle pro-tection with one short cycle on unit flameroll-out switch or 4 continuous short cycleson the high temperature limit switch. Faultindication shall be made using an LED.
3. Standard heat exchanger construction:a. Heat exchanger shall be of the tubular-section
type constructed of a minimum of 20-gagesteel coated with a nominal 1.2 mil aluminum-silicone alloy to aid with corrosion resistance.
b. Burners shall be of the inshot type con-structed of aluminum-coated steel.
c. Burners shall incorporate orifices for ratedheat output up to 2000 ft (610 m) eleva-tion. Additional accessory kits may berequired for applications above 2000 ft(610 m) elevation, depending on local gassupply conditions.
d. Each heat exchanger tube shall containmultiple dimples for increased heatingeffectiveness.
4. Optional stainless steel heat exchangerconstruction:a. Use energy saving, direct-spark ignition
system.b. Use a redundant main gas valve.c. Burners shall be of the inshot type con-
structed of aluminum-coated steel.d. All gas piping shall enter the unit cabinet at
a single location on side of unit (verticalplane).
e. The optional stainless steel heat exchangershall be of the tubular-section type, con-structed of a minimum of 20-gage type 409stainless steel.
f. Type 409 stainless steel shall be used inheat exchanger tubes and vestibule plate.
g. Complete stainless steel heat exchangerallows for greater application flexibility.
5. Induced draft combustion motor and blower:a. Shall be a direct-drive, single inlet, forward-
curved centrifugal type.b. Shall be made from steel with a corrosion-
resistant finish.c. Shall have permanently lubricated sealed
bearings.d. Shall have inherent thermal overload
protection.
e. Shall have an automatic reset feature.I. (23 81 19.13.I.) Coils:
1. Standard aluminum fin/copper tube coils:a. Standard evaporator and condenser coils
shall have aluminum lanced plate finsmechanically bonded to seamless internallygrooved copper tubes with all joints brazed.
b. Evaporator coils shall be leak tested to150 psig, pressure tested to 450 psig, andqualified to UL 1995 burst test at 1775 psig.
c. Condenser coils shall be leak tested to150 psig, pressure tested to 650 psig, andqualified to UL 1995 burst test at 1980 psig.
2. Optional pre-coated aluminum-fin condensercoils:a. Shall have a durable epoxy-phenolic coating
to provide protection in mildly corrosivecoastal environments.
b. Coating shall be applied to the aluminum finstock prior to the fin stamping process tocreate an inert barrier between the alumi-num fin and copper tube.
c. Epoxy-phenolic barrier shall minimize gal-vanic action between dissimilar metals.
d. Corrosion durability of fin stock shall be con-firmed through testing to be no less than1000 hours salt spray per ASTM B117-90.
e. Corrosion durability of fin stock shall beconfirmed through testing to have no visiblecorrosion after a 48-hour immersion in aroom temperature solution of 5% salt, 1%acetic acid.
f. Fin stock coating shall pass 2000 hours ofthe following: one week exposure in theprohesion chamber followed by one weekof accelerated ultraviolet light testing. Pro-hesion chamber: the solution shall contain3.5% sodium chloride and 0.35% ammo-nium sulfate. The exposure cycle is onehour of salt fog application at ambient fol-lowed by one hour drying at 95°F (35°C).
3. Optional copper-fin evaporator and condensercoils:a. Shall be constructed of copper fins mechan-
ically bonded to copper tubes and coppertube sheets.
b. Galvanized steel tube sheets shall not beacceptable.
c. A polymer strip shall prevent coil assemblyfrom contacting the sheet metal coil pan tominimize potential for galvanic corrosionbetween coil and pan.
4. Optional E-coated aluminum-fin, evaporatorand condenser coils:a. Shall have a flexible epoxy polymer coating
uniformly applied to all coil surface areaswithout material bridging between fins.
Guide specifications (cont)
71
b. Coating process shall ensure complete coilencapsulation of tubes, fins, and headers.
c. Color shall be high gloss black with gloss perASTM D523-89.
d. Uniform dry film thickness from 0.8 to 1.2 milon all surface areas including fin edges.
e. Superior harness characteristics of 2H perASTM D3363-92A and cross-hatch adhe-sion of 4B-5B per ASTM D3359-93.
f. Impact resistance shall be up to 160 in.-lb(ASTM D2794-93).
g. Humidity and water immersion shall be up tominimum 1000 and 250 hours respectively(ASTM D2247-92 and ASTM D870-92).
h. Corrosion durability shall be confirmedthrough testing to be no less than6000 hours salt spray per ASTM B117-90.
5. Standard ALL Aluminum Novation® Coils:a. Standard condenser coils shall have all alu-
minum Novation Heat Exchanger Technol-ogy design consisting of aluminum multi-portflat tube design and aluminum fin. Coils shallbe a furnace brazed design and containepoxy lined shrink wrap on all aluminum tocopper connections.
b. Condenser coils shall be leak tested to150 psig, pressure tested to 650 psig, andqualified to UL 1995 burst test at 1980 psig.
6. Optional E-coated aluminum-fin, aluminumtube condenser coils:a. Shall have a flexible epoxy polymer coating
uniformly applied to all coil external surfaceareas without material bridging between fins.
b. Coating process shall ensure complete coilencapsulation of tubes, fins, and headers.
c. E-coat thickness of 0.8 to 1.2 mil with topcoat having a uniform dry film thickness from1.0 to 2.0 mil on all external coil surfaceareas, including fin edges, shall be provided.
d. Shall have superior hardness characteristicsof 2H per ASTM D3363-00 and cross-hatch adhesion of 4B-5B per ASTMD3359-02.
e. Shall have superior impact resistance withno cracking, chipping or peeling per NSF/ANSI 51-2002 Method 10.2.
J. (23 81 19.13.J.) Refrigerant components:1. Refrigerant circuit shall include the following
control, safety, and maintenance features:a. Fixed orifice metering system (on non-
Humidi-MiZer® units) provides correct distri-bution of two-phase refrigerant by includingmultiple fixed orifice devices in each refriger-ation circuit. Each orifice is to be optimizedto the coil circuit it serves.
b. Thermostatic Expansion Valve (TXV) shallhelp provide optimum performance acrossthe entire operating range. Shall containremovable power element to allow changeout of power element and bulb withoutremoving the valve body.
c. Refrigerant filter drier - Solid core design.d. Service gage connections on suction and
discharge lines.e. Pressure gage access through a specially
designed access screen on the side of theunit.
2. Compressors:a. Unit shall use fully hermetic, scroll com-
pressor for each independent refrigerationcircuit.
b. Models shall be available with 2 compres-sor/2-stage cooling.
c. Compressor motors shall be cooled by refrig-erant gas passing through motor windings.
d. Compressors shall be internally protectedfrom high discharge temperature conditions.
e. Compressors shall be protected from anover-temperature and over-amperage condi-tions by an internal, motor overload device.
f. Compressor shall be factory mounted onrubber grommets.
g. Compressor motors shall have internal linebreak thermal, current overload and highpressure differential protection.
h. Crankcase heaters shall not be required fornormal operating range, unless provided bythe factory.
K. (23 81 19.13.K.) Filter section:1. Filters access is specified in the unit cabinet
section of this specification.2. Filters shall be held in place by a preformed,
4. Filters shall be standard, commercially avail-able sizes.
5. Only one size filter per unit is allowed.6. 4-in. filter capability is possible with a field-
installed pre-engineered slide out filter trackaccessory. 4-in. filters are field furnished.
L. (23 81 19.13.L.) Evaporator fan and motor:1. Evaporator fan motor:
a. Shall have inherent automatic-reset thermaloverload protection or circuit breaker.
b. Shall have a maximum continuous bhp rat-ing for continuous duty operation; no safetyfactors above that rating shall be required.
72
2. Belt-driven evaporator fan:a. Belt drive shall include an adjustable-pitch
motor pulley and belt break protectionsystem.
b. Shall use rigid pillow block bearing systemwith lubricant fittings at accessible bearingor lubrication line.
c. Blower fan shall be double-inlet type withforward-curved blades.
d. Shall be constructed from steel with a finishthat aids with corrosion resistance and that isdynamically balanced.
M. (23 81 19.13.M.) Condenser fans and motors:1. Condenser fan motors:
a. Shall be a totally enclosed motor.b. Shall use permanently lubricated bearings.c. Shall have inherent thermal overload pro-
tection with an automatic reset feature.d. Shall use a shaft-down design.
2. Condenser fans:a. Shall be a direct-driven propeller type fan.b. Shall have aluminum blades riveted to steel
spiders that have corrosion resistant prop-erties and shall be dynamically balanced.
N. (23 81 19.13.N.) Special features options andaccessories:
1. Staged Air Volume System (SAV™) for 2-stagecooling models only:a. Evaporator fan motor:
1.) Shall have permanently lubricatedbearings.
2.) Shall have a maximum continuous bhprating for continuous duty operation;no safety factors above that rating.
3.) Shall be Variable Frequency duty and2-speed control.
4.) Shall contain motor shaft grounding ringto prevent electrical bearing fluting dam-age by safely diverting harmful shaftvoltages and bearing currents to ground.
2. Variable frequency drive (VFD). Only availableon 2-speed indoor fan motor option (SAV):a. Factory-supplied VFDs qualify, through
ABB, for a 12-month warranty from date ofcommissioning or 18 months from date ofsale, whichever occurs first.
b. Shall be installed inside the unit cabinet,mounted, wired and tested.
c. Shall contain Electromagnetic Interference(EMI) frequency protection.
d. Insulated gate bi-polar transistors (IGBT)used to produce the output pulse widthmodulated (PWM) waveform, allowing forquiet motor operation.
e. Self diagnostics with fault and power codeLED indicator. Field accessory Display Kitavailable for further diagnostics and specialsetup applications.
f. RS485 capability standard.g. Electronic thermal overload protection.h. 5% swinging chokes for harmonic reduction
and improved power factor.i. All printed circuit boards shall be conformal
coated.3. Integrated EconoMi$er® IV, EconoMi$er 2, and
ing blade design type capable of simultane-ous economizer and compressor operation.
b. Independent modules for vertical returnconfiguration shall be available.
c. Damper blades shall be galvanized steel withcomposite gears. Plastic or composite bladeson intake or return shall not be acceptable.
d. Shall include all hardware and controls to pro-vide free cooling with outdoor air when tem-perature and/or humidity are below setpoints.
e. Shall be equipped with gear driven dampersfor both the outdoor ventilation air and thereturn air for positive air stream control.
f. Low leak rate models shall be equippedwith dampers not to exceed 2% leakage at1 in. wg pressure differential.
g. Economizer controller on EconoMi$er IVmodels shall be Honeywell W7212 thatprovides:1.) Combined minimum and DCV maximum
damper position potentiometers withcompressor staging relay.
2.) Functions with solid state analogenthalpy or dry bulb changeover con-trol sensing.
3.) Contain LED indicates for: when freecooling is available, when module is inDCV mode, when exhaust fan contact isclosed.
h. Economizer controller on EconoMi$er Xmodels shall be the Honeywell W7220 thatprovides: 1.) 2-line LCD interface screen for setup,
configuration, and troubleshooting.2.) On-board Fault Detection and Diagnos-
tics (FDD) that senses and alerts whenthe economizer is not operating prop-erly, per California Title 24.
3.) Sensor failure loss of communicationidentification.
4.) Automatic sensor detection.5.) Capabilities for use with multi-speed
indoor fan systems.
Guide specifications (cont)
73
6.) Utilize digital sensors: dry-bulb andenthalpy.
i. Economizer controller on EconoMi$er2 models with PremierLink™ controllershall be 4-20mA design and controlled bythe PremierLink controller. PremierLinkdoes not comply with California Title 24Fault Detection and Diagnostic (FDD)requirements.
j. Economizer controller on EconoMi$er 2models with RTU Open models shall be 4-20mA design controlled directly by the RTUOpen controller. RTU Open meets Califor-nia Title 24 Fault Detection and Diagnostic(FDD) requirements.
k. Shall be capable of introducing up to 100%outdoor air.
l. Shall be equipped with a barometric reliefdamper capable of relieving up to 100%return air and contain seals that meetASHRAE 90.1-2016 and IECC-2015requirements.
m. Shall be designed to close damper(s) duringloss-of-power situations with spring returnbuilt into motor.
n. Dry bulb outdoor air temperature sensor shallbe provided as standard. Enthalpy sensor isalso available for factory-installed economiz-ers only. Outdoor air sensor setpoint shall beadjustable and shall range from 40°F to100°F (4°C to 38°C.) Additional sensoroptions shall be available as accessories.
o. The economizer controller shall also pro-vide control of an accessory power exhaustunit function. Factory set at 100%, with arange of 0% to 100%.
p. The economizer shall maintain minimumairflow into the building during occupiedperiod and provide design ventilation ratefor full occupancy.
q. Dampers shall be completely closed whenthe unit is in the unoccupied mode.
r. Economizer controller shall accept a 2 to10 Vdc CO2 sensor input for IAQ/DCVcontrol. In this mode, dampers shall modu-late the outdoor air damper to provide ven-tilation based on the sensor input.
s. Compressor lockout temperature onW7220 is adjustable from –45°F to 80°F(43°C to 27°C), set at a factory default of32°F (0°C). Others shall open at 35°F (2°C)and closes at 50°F (10°C).
t. Actuator shall be direct coupled to econo-mizer gear. No linkage arms or control rodsshall be acceptable.
u. Economizer controller shall provide indica-tions when in free cooling mode, in the
DCV mode, or the exhaust fan contact isclosed.
4. Integrated EconoMi$er® 2, and EconoMi$er XUltra Low Leak rate models. (Factory or field-installed):a. Integrated, gear driven opposing modulat-
ing blade design type capable of simultane-ous economizer and compressor operation.
b. Independent modules for vertical returnconfiguration shall be available.
c. Damper blades shall be galvanized steel withcomposite gears. Plastic or composite bladeson intake or return shall not be acceptable.
d. Shall include all hardware and controls to pro-vide free cooling with outdoor air when tem-perature and/or humidity are belowsetpoints.
e. Shall be equipped with gear driven dampersfor both the outdoor ventilation air and thereturn air for positive air stream control.
f. Ultra Low Leak design meets CaliforniaTitle 24 section 140.4 and ASHRAE 90.1-2016 and IECC-2015 requirements of 4 cfmper sq ft on the outside air dampers and10 cfm per sq ft on the return dampers.
g. Economizer controller on EconoMi$er Xmodels shall be the Honeywell W7220 thatprovides: 1.) 2-line LCD interface screen for setup,
configuration and troubleshooting.2.) On-board Fault Detection and Diagnos-
tics (FDD) that senses and alerts whenthe economizer is not operating prop-erly, per California Title 24 Fault Detec-tion and Diagnostic (FDD) requirements.
3.) Sensor failure loss of communicationidentification.
4.) Automatic sensor detection.5.) Capabilities for use with multiple-speed
indoor fan systems. 6.) Utilize digital sensors: Dry bulb and
Enthalpy.h. Economizer controller on EconoMi$er 2
models with RTU Open models shall be 4to 20mA design controlled directly by theRTU Open controller. RTU Open meetsCalifornia Title 24 Fault Detection andDiagnostic (FDD) requirements.
i. Shall be capable of introducing up to 100%outdoor air.
j. Shall be equipped with a barometric reliefdamper capable of relieving up to 100%return air and contain seals that meetASHRAE 90.1-2016 and IECC-2015requirements.
k. Shall be designed to close damper(s) duringloss-of-power situations with spring returnbuilt into motor.
74
l. Dry bulb outdoor air temperature sensor shallbe provided as standard. Enthalpy sensor isalso available for factory-installed economiz-ers only. Outdoor air sensor setpoint shall beadjustable and shall range from 40°F to100°F (4°C to 38°C). Additional sensoroptions shall be available as accessories.
m. The economizer controller shall also pro-vide control of an accessory power exhaustunit function. Factory set at 100%, with arange of 0% to 100%.
n. The economizer shall maintain minimum air-flow into the building during occupied periodand provide design ventilation rate for fulloccupancy.
o. Dampers shall be completely closed whenthe unit is in the unoccupied mode.
p. Economizer controller shall accept a 2 to10 Vdc CO2 sensor input for IAQ/DCVcontrol. In this mode, dampers shall modu-late the outdoor air damper to provide ven-tilation based on the sensor input.
q. Compressor lockout temperature onW7220 is adjustable from –45°F to 80°F(43°C to 27°C), set at a factory default of32°F (0°C). Others shall open at 35°F (2°C)and closes at 50°F (10°C).
r. Actuator shall be direct coupled to econo-mizer gear. No linkage arms or control rodsshall be acceptable.
s. Economizer controller shall provide indica-tions when in free cooling mode, in the DCVmode, or the exhaust fan contact is closed.
5. Two-Position Motorized Damper:a. Damper shall be a 2-position damper. Damper
travel shall be from the full closed position tothe field adjustable %-open setpoint.
b. Damper shall include adjustable dampertravel from 25% to 100% (full open).
c. Damper shall include single or dual blade,gear driven dampers and actuator motor.
d. Actuator shall be direct coupled to dampergear. No linkage arms or control rods shallbe acceptable.
e. Damper will admit up to 100% outdoor airfor applicable rooftop units.
f. Damper shall close upon indoor (evapora-tor) fan shutoff and/or loss of power.
g. The damper actuator shall plug into therooftop unit’s wiring harness plug. No hardwiring shall be required.
h. Outside air hood shall include aluminumwater entrainment filter.
i. Not for use with Staged Air Volume (SAV™)models.
6. Manual damper:a. Manual damper package shall consist of
damper, air inlet screen, and rain hoodwhich can be preset to admit up to 25%outdoor air for year round ventilation.
b. Not for use with Staged Air Volume (SAV)models.
7. Humidi-MiZer® adaptive dehumidification sys-tem (not available on 30 size models):a. The Humidi-MiZer Adaptive Dehumidification
System shall be factory-installed in 48TC17-28 models with RTPF (round tube plate-fin)condenser coils, and shall provide greaterdehumidification of the occupied space by twomodes of dehumidification operations besidesits normal design cooling mode:1.) Subcooling mode further sub cools the
hot liquid refrigerant leaving the con-denser coil when both temperature andhumidity in the space are not satisfied.
2.) Hot gas reheat mode shall mix a por-tion of the hot gas from the dischargeof the compressor with the hot liquidrefrigerant leaving the condenser coil tocreate a two-phase heat transfer in thesystem, resulting in a neutral leaving airtemperature when only humidity in thespace is not satisfied.
3.) Includes head pressure controller.8. Head pressure control package (Motormaster®):
a. Controller shall control coil head pressureby condenser-fan speed modulation or con-denser-fan cycling and wind baffles.
b. Shall consist of solid-state control and con-denser-coil temperature sensor to maintaincondensing temperature between 90°F(32°C) and 110°F (43°C) at outdoor ambienttemperatures down to –20°F (–29°C).
9. Propane conversion kit:a. Package shall contain all the necessary
hardware and instructions to convert a stan-dard natural gas unit for use with liquefiedpropane. Kits shall be available for eleva-tions from 0 up to 14,000 ft (4,267m).
10. Condenser coil hail guard assembly:a. Shall protect against damage from hail.b. Shall be louvered style design.
11. Unit-mounted, non-fused disconnect switch:a. Switch shall be factory-installed, internally
mounted.b. National Electric Code (NEC) and UL
approved non-fused switch shall provideunit power shutoff.
c. Shall be accessible from outside the unit.d. Shall provide local shutdown and lockout
capability.
Guide specifications (cont)
75
e. Sized only for the unit as ordered from thefactory. Does not accommodate field-installed devices.
1.) Outlet shall be powered from main linepower to the rooftop unit.
2.) Outlet shall be powered from line sideof disconnect by installing contractor, asrequired by code. If outlet is poweredfrom load side of disconnect, unit elec-trical ratings shall be ETL certified andrated for additional outlet amperage.
3.) Outlet shall be factory-installed and inter-nally mounted with easily accessible115-v female receptacle.
4.) Outlet shall include 15 amp GFI recep-tacles with independent fuse protection.
5.) Voltage required to operate conve-nience outlet shall be provided by a fac-tory-installed step-down transformer.
6.) Outlet shall be accessible from outsidethe unit.
7.) Outlet shall include a field-installed “Wetin Use” cover.
b. Factory-installed non-powered convenienceoutlet:1.) Outlet shall be powered from a separate
115-120v power source.2.) A transformer shall not be included.3.) Outlet shall be factory-installed and
internally mounted with easily accessible115-v female receptacle.
4.) Outlet shall include 15 amp GFIreceptacles.
5.) Outlet shall be accessible from outsidethe unit.
6.) Outlet shall include a field-installed “Wetin Use” cover.
c. Field-installed non-powered convenienceoutlet:1.) Outlet shall be powered from a separate
115-120v power source.2.) A transformer shall not be included.3.) Outlet shall be factory-installed and
internally mounted with easily accessible115-v female receptacle.
4.) Outlet shall include 20 amp GFI recepta-cles. This kit provides a flexible installationmethod which allows code compliance forheight requirements of the GFCI outletfrom the finished roof surface as well asthe capability to relocate the outlet to amore convenient location.
5.) Outlet shall be accessible from outsidethe unit.
6.) Outlet shall include a field-installed “Wetin Use” cover.
13. Flue discharge deflector:a. Flue discharge deflector shall direct unit
exhaust vertically instead of horizontally.b. Deflector shall be defined as a “natural
draft” device by the National Fuel and Gas(NFG) code.
14. Centrifugal propeller power exhaust:a. Power exhaust shall be used in conjunction
with an integrated economizer.b. Independent modules for vertical return
configurations shall be available.c. Power exhaust shall be controlled by econo-
mizer controller operation. Exhaust fansshall be energized when dampers open pastthe 0-100% adjustable setpoint on theeconomizer control.
15. Roof curbs (vertical):a. Full perimeter roof curb with exhaust capa-
bility providing separate air streams forenergy recovery from the exhaust air with-out supply air contamination.
b. Formed galvanized steel with wood nailerstrip and shall be capable of supportingentire unit weight.
c. Permits installation and securing of ductworkto curb prior to mounting unit on the curb.
16. Adapter curb (vertical):a. Full perimeter, fully assembled, and welded
roof curb with exhaust capability providingseparate air streams for energy recoveryfrom the exhaust air without supply aircontamination.
b. Formed galvanized steel with wood nailerstrip and shall be capable of supportingentire unit weight.
c. Permits installation of new 48TC17-28 mod-els to past Carrier design curb models: DP,DR, HJ, TM, and TJ. (Not for 48TJE024-28models.) Check with Carrier sales expert forfurther details and information.
17. High altitude gas conversion kit:a. Package shall contain all the necessary
hardware and instructions to convert astandard natural gas unit to operate from3,000 to 10,000 ft (914 to 3048 m)elevation and 10,001 to 14,000 ft (3049 to4267 m) elevation.
18. Outdoor air enthalpy sensor:a. The outdoor air enthalpy sensor shall be
used to provide single enthalpy control.When used in conjunction with a return airenthalpy sensor, the unit will provide differ-ential enthalpy control. The sensor allowsthe unit to determine if outside air is suit-able for free cooling.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.Pg 76 Catalog No. 04-52480074-01 Printed in U.S.A. Form 48TC-17-30-V-05PD
Replaces: 48TC-17-30-V-04PD
Carrier Corporation • Syracuse, New York 13221 10-19
19. Return air enthalpy sensor:a. The return air enthalpy sensor shall be
used in conjunction with an outdoor airenthalpy sensor to provide differentialenthalpy control.
20. Indoor air quality (CO2) sensor:a. Shall be able to provide demand ventila-
tion indoor air quality (IAQ) control.b. The IAQ sensor shall be available in duct
mount, wall mount, or wall mount withLED display. The setpoint shall haveadjustment capability.
21. Smoke detectors:a. Shall be a four-wire controller and detector.b. Shall be environmental compensated with
differential sensing for reliable, stable, anddrift-free sensitivity.
c. Shall use magnet-activated test/reset sen-sor switches.
d. Shall have tool-less connection terminalaccess.
e. Shall have a recessed momentary switchfor testing and resetting the detector.
f. Controller shall include:1.) One set of normally open alarm initia-
tion contacts for connection to an ini-tiating device circuit on a fire alarmcontrol panel.
2.) Two Form-C auxiliary alarm relays forinterface with rooftop unit or otherequipment.
3.) One Form-C supervision (trouble)relay to control the operation of theTrouble LED on a remote test/resetstation.
4.) Capable of direct connection to twoindividual detector modules.
5.) Can be wired to up to 14 other ductsmoke detectors for multiple fan shut-down applications.
22. Horn/strobe annunciator:a. Provides an audible/visual signaling device
for use with factory-installed option orfield-installed accessory smoke detectors.1.) Requires installation of a field-supplied
24-v transformer suitable for 4.2 VA(AC) or 3.0 VA (DC) per horn/strobeaccessory.
2.) Requires field-supplied electrical box,North American 1-gang box, 2-in.(51 mm) x 4-in. (102 mm).
3.) Shall have a clear colored lens.23. Winter start kit:
a. Shall contain a bypass device around thelow pressure switch.
b. Shall be required when mechanical cool-ing is required down to 25°F (–4°C).
c. Shall not be required to operate on aneconomizer when below an outdoor ambi-ent of 40°F (4°C).
24. Time guard:a. Shall prevent compressor short cycling by
providing a 5-minute delay (±2 minutes)before restarting a compressor after shut-down for any reason.
b. One device shall be required per compressor.25. Display kit for variable frequency drive (VFD):
a. Kit allows the ability to access the VFDcontroller programs to provide specialsetup capabilities and diagnostics.
b. Kit contains display module and communi-cation cable.
c. Display kit can be permanently installed inthe unit or used on any SAV™ system VFDcontroller as needed.
26. Condensate Overflow Switch:a. This sensor and related controller monitors
the condensate level in the drain pan andshuts down compression operation whenoverflow conditions occur. It includes:1.) Indicator light — solid red (more than
10 seconds on water contact - com-pressors disabled), blinking red (sensordisconnected).
2.) 10 second delay to break — elimi-nates nuisance trips from splashing orwaves in pan (sensor needs 10 sec-onds of constant water contact beforetripping).
3.) Disables the compressor(s) operationwhen condensate plug is detected, butstill allows fans to run for Economizer.
27. Hinged access panels:a. Shall provide easy access through hinged
access doors with vinyl coated door retainers.b. Shall be on major panels of – filter, control